I would always recommend the subwoofer crawl! its crude, but works great. My instict is one behind the couch (opposite position 2), and the other to the left side of the room. I've had some issues in my room with corner loading, but if you do the crawl, you should be able to identify pretty easily if the back left corner (position 4) would get boomy/muddy.
You're in good hands, Sven!
Sup, Bill!!! Hope all is well!
Oh, Sven... your last post... I think its generally accepted that you might get a better low end extension with the SVS, and a little better Mid-Bass with the Hsu's... but with all of these subs, you kind of end up splitting hairs. In general, you might have more bang for the buck with HSU, and they are no slouch by all reports. But unless you are going to drive to and from Anaheim, there isn't an easy way to audition those in your home.
SVS might be the ticket. Regardless, most of these don't disappoint.
Cheers!